Condenser frame construction



Oct. 24-, 1933; E M s 7 1,932,328

CONDENSER FRAME CONSTRUCTION Filed Feb. 14, 1929 Patented Oct. 24, 1933 UNITED STATES CONDENSER FRAME CONSTRUCTION Emerson H. Tompkins, Waterbury, Conn., assignor, by mesne assignments, to General Instrument Corporation, New York, N. Y., a corporation of New York Application February 14, 1929. Serial No. 339,781

Claims.

for mounting variable electrical condensers.

It is an object of the invention to provide a frame substantially free from strains and stresses which would tend to alter relative positions of the parts and produce warping. thereby changing the capacity of the condenser.

With these and other objects in view, the invention consists in the features, combinations, details of construction, and arrangements of parts which will first be described in connection with the accompanying drawing and then more particularly pointed out.

In the drawing:

Figure 1 is a perspective view of a frame constructed in accordance with the present invention showing a gang of condensers mounted therein;

Figure 2 is a perspective view of the-frame of Figure 1 with the condensers removed;

Figure 3 is a development of the main frame member before being bent to shape;

Figure 4 is a perspective view of one of the cross members of the frame; and

Figure 5 is a sectional plan view of a detail of construction.

Referring to the drawing, there are shown a plurality of condensers, the rotor elements 2 of which are mounted on a common shaft 3. In order that the respective relation of the rotors and stators of the various condensers may be ac curately maintained, there is provided a supporting frame in which there is substantial freedom from strains and stresses. This is accomplished by forming the frame of a minimum number of parts and assembling and securing the parts together so as not to impart strains and stresses thereto.

Although capable of various constructions, as here shown as an example, the illustrated embodiment comprises a main frame member 5 having a bottom portion or base 6 and upstanding parallel sides '7 substantially at right angles to the base. Means are provided for maintaining the sides in their parallel relation at right angles to the base and, to this end, cross members 8, 9 extend between the opposite sides 7 and are affixed thereto and to the base 6.

Means are provided for securing the cross members 8, 9 to the main frame 5 and in structures embodying the invention to what is now considered the best advantage, this is obtained by providing the members and main frame with cooperating slots and fingers. Although capable of various constructions, as here shown as an ex ample, the main frame member 5 has out therein suitably spaced slots or notches 10 in line with the cross members 8, 9. Co-operating with these slots, the cross members 8, 9, have formed therein extensions or fingers 11 at corresponding intervals, said extensions being adapted to fit This invention relates to frame constructions into the slots 10. The slots are so dimensioned that the lit of extensions 11 therein is tight and snug. The extensions are provided in the sides and bottoms of the cross members and engage slots in the sides and bottoms of the main frame member. In order to prevent the extensions from being accidentally removed from the slots and to provide a permanent connection, the extensions 11 may be soldered into the slots 10. The cross members are thus firmly secured to the main frame but the securing means do not create strains or stresses tending to produce warping and consequent change of capacity.

The resulting construction resembles a coverless rectangular box, the size and proportion of which may be altered to correspond to the size of the condensers to be carried therein. If the frame is to support a plurality of condenser elements, as, for instance, in the arrangements known as a gang of condensers which comprises a common shaft and operating dial, there may be provided, at frequent intervals, additional intermediate cross members 12 also having extensions 11 cooperating with slots 14 in the main frame. These additional intermediate cross members serve to strengthen the frame construction and further maintain it in proper alignment.

The condenser illustrated as an example of condensers which may be supported in the frame comprises an operating shaft 3 which is journailed for rotation in oppositely aligned openings 16 provided in the cross members 8, 9. For operating this shaft it is extended beyond the cross member 8 outside of the frame for the reception of a knob or other controlling device (not shown).

The metal of the cross members is swelled upwardly as at 17 to provide the bearings for the shaft 16. Integral collars, 18, are shown on the cross members to produce longer shaft bearings. The intermediate cross members are cut away as at 19 for the accommodation of the shaft.

As in the well known form of variable condenser, the shaft 3 carries a rotor element or elements 2 above mentioned, which -may comprise a plurality of'spaced parallel conducting plates 21. As here shown, the plates 21 are given any desired shape and are secured, as by soldering, in parallel slots 22 cut in the outer surface of a sleeve 23 which iskeyed to the shaft 3 for turning therewith.

The rotor elements respectively, coact with stator elements 24 comprising a plurality of spaced parallel conducting plates 25 between which the rotor plates 21 may be moved for varying capacity values. For spacing these plates 25 the necessary distance apart, they are provided at their ends with small extensions 26 which are secured in slots 27 formed in holding members 28, the slots 27 being spaced apart a distance equal to the desired plate spacing, or dielectric thickness.

Means are included for mounting these stator plates 25 on the frame from which they are also to be insulated. This may be accomplished by securing the holding members 28, not directly to the frame, but to an insulating medium in turn secured to the frame.

In structures embodying the invention to what is now considered the best advantage, each of the holding members 28 is mounted on a plate 29 of insulating material and these plates 29 are in turn secured to the frame 5. Although capable of various construction, as here shown, the upstanding sides or walls '7 of the frame are provided with oppositely facing openings 30 sufficiently large so that the holding members 28 may freely extend through to a position such that the edges of the holding members 28 are flush with the outside surface of the side walls 7.

Secured to the edge of the holding members 28, as by screws 31, are the insulating plates 29 which may be flat against the side walls- 7 of the frame over the openings 30 and be secured to said walls '7 as by screws 33.

In this way the stators 24 are insulated from but directly supported on the frame.

Electrical access may be had to the stator elements 24 by providing conducting plates 34 on the outer face of the insulating plates 29 through which the screws 31 pass. If desired, these conducting plates 34 may have formed thereon a pierced projection 35 to which a wire may be conveniently attached.

In many types of radio receiving circuits, small auxiliary or compensating condensers are included in circuit with the main condensers, which compensating condensers may be conveniently mounted on said insulating plate 29, the conducting plate 34 advantageously serving as one element of the compensating condenser.

In order to lighten the frame construction to a minimum weight, strength, and to provide access to the interior of the frame, the base 6 is cut away between the cross members, as at 36, leaving members 37 sumciently large to support the intermediate and end cross members 8, 9, 12. In like manner, the openings 30 in the side walls 7, through which the holding members 28 extend, may be increased in size, thus, also diminishing the frame weight.

Means may be provided for mounting the frame within a box or other cabinet and for this purpose the frame is drilled with holes 38' through which mounting screws may be threaded or rivets passed.

With the construction described there is provided a compact simple frame structure of few parts, which may, when assembled, be accurately aligned. Furthermore, the parts making up the structure may all be stamped out of flat stock and the slots and screw holes may all be out while flat, if desired, in the same operation,

thus making the frame economical and cheap to manufacture.

What is claimed is: i

1. A condenser construction including stator plates, rotor 'plates interleaved therewith and spaced therefrom, a rotor plate shaft anda nonwarping frame for maintaining the spacng between said rotor plates and stator plates, said frame comprising a stamping providing a bottom having an opening and opposed s des. folded therefrom and forming with said b011 0! a Chane without sacrificing nel member, shaft supporting plates secured to said channel member at opposite ends thereof, said rotor plates being carried by said shaft and means carried by the channel member for sup porting said stator plates between said opposed folded sides.

2. A gang condenser construction including a plurality of separate groups of stator plates, a group of rotor plates interleaved with each group of stator plates and spaced therefrom, a rotor plate shaft, and a non-warping frame for maintaining the spacing between the stator plates of each group and their associated rotor plates, said frame comprising a stamping providing a bottom having openings therein and opposed sides folded therefrom and forming with said bottom a channel member, sad sides having opposite openings therein, means in said openings for mounting the groups of stator plates in said channel member, rotor shaft supporting end plates closing opposite ends of said channel member, means secur- :ng said end plates to said channel member, and shielding partition plates in said channel member between the bottom openings thereof and secured to said folded sides.

3. A condenser chassis for a multiple unit variable condenser comprising a cradle having upwardly extending walls at opposite sides thereof, a multiplicity of frame members disposed at spaced intervals laterally of said cradle, means interconnecting said frame members with said cradle comprising lugs on said members projecting through laterally disposed apertures in the side walls and the bottom of said cradle, a rotatable shaft journaled in the frame members at each end of sa d cradle, sets of stator plates insulatingly supported between the sides of said cradle and between adjacent pairs of said frame members, and sets of rotor plates carried by said rotatable shaft and adapted to be variably interleaved with the sets of stator plates supported in said cradle.

4. A condenser construction including stator plates, rotor plates interleaved therewith and spaced therefrom, a rotor plate shaft and a nonwarping'frame for maintaining the spacing between said rotor plates and stator plates, said frame comprising a stamping providing a bottom and opposed sides folded therefrom and forming with said bottom an open ended channel member, separate shaft supporting plates secured to said channel member at opposite ends thereof, said rotor plates being carried by said shaft, and means carried by the channel member for supporting said stator plates between said opposed folded sides.

5. A gang condenser construction including a plurality of separate groups of stator plates, a group of rotor plates interleaved with each group of stator plates and spaced therefrom, a rotor plate shaft, and a non-warping frame for maintaining the spacing between the stator plates of each group and their associated rotor plates, said frame comprsing a stamping providing a bottom and opposed sides folded therefrom and forming with said bottom an open ended channel. member, said sides having opposite openings therein, means in said openings for mounting the group of stator plates in said channel member, separate rotor shaft supporting end plates closing opposite ends of said channel member, means securing said end plates to said channel member, and spaced shielding partition plates in said channel member secured to said folded s des.

EMERSON H. TOMPKINS. 

